A pin heater in a sheathed-element glow plug for diesel engines, which has at least one essentially internal insulating layer and at least one essentially external conductive layer, both layers including ceramic composite structures, is already known from German Published Patent Application No. 100 53 327. In this way, the external conductive layer is U-shaped in cross-section in the region of a combustion chamber side tip of the pin heater, so that the external conductive layer encloses the insulating layer in the region of the combustion chamber side tip of the pin heater.